Recent Obesity Studies Deflate Earlier Finding

Repeated studies by a team of researchers, including several UAB faculty and graduate research students, have been unable to replicate findings of an earlier study showing the gastrointestinal hormone PYY3-36 decreases appetite and weight gain in rodents.

Posted on July 7, 2004 at 12:00 p.m.

BIRMINGHAM, AL — Repeated studies by a team of researchers, including several UAB faculty and graduate research students, have been unable to replicate findings of an earlier study showing the gastrointestinal hormone PYY3-36 decreases appetite and weight gain in rodents. A summary of findings will be published in the July 8 issue of Nature.

“The original study heralded the hormone as a potential treatment for obesity and was considered a breakthrough in obesity research,” said Mary Boggiano, Ph.D., associate professor of psychology at UAB. “But our findings call into question the use of this hormone as an effective anti-obesity drug.”

Matthias Tschop, Ph.D., associate professor of psychiatry with the University of Cincinnati, led the research team comprised of 42 investigators from 15 international institutions. “We employed the latest obesity research methodology to carefully characterize the therapeutic effects of the hormone,” said David B. Allison, Ph.D., professor of public health with the department of biostatistics at UAB and director of UAB’s Clinical Nutrition Research Center. “Surprisingly, despite substantial effort, PYY3-36 failed to reduce food intake or body weight across these studies.”

The reason for the discrepancy between the original study and recent findings is unclear. “Statistically, the probability of obtaining such a difference by chance is on the order of one in a million,” said Allison, who provided statistical support for recent studies. “Still, our findings stand in direct contrast to the initial finding.”

Authors note studies indicate the therapeutic value of the hormone may be limited because an effective drug must be proven to work across a range of situations. “We want to share this information with patients and doctors who are fighting obesity as well as fellow scientists who are facing the difficult decision of which molecular target to invest their limited research resources on or which drug candidate may justify expensive clinical trials,” Boggiano said.